Motor reversing control with counterweight to reduce reaction torques



3,188,546 UNTERWEIGHT June 8, 1965 J. E. DAWKINS MOTOR REVERSING CONTROL WITH GO TO REDUCE REACTION TORQUES 3 Sheets-Sheet 1 Filed Feb. 27, 1963 INVENTOR. JOHN E. DAWK/IVS ATTORNEY June 8, 1965 J. E. MOTOR REVERSING GO TO REDUCE REACTI Filed Feb. 27, 1963 NTROL DAWKINS WITH COUNTERWEIGHT ON IORQUES 3 Sheets-Sheet 2' INVENTOR JOHN E. UAW/(l/VS ATTORNEY June 8, 1965 J. E. DAWKINS 3,183,546

MOTOR REVERSING CONTROL WITH COUNTERWEIGHT To REDUCE REACTION TQRQUES Filed Feb. 27, 1963 3 Sheets-Sheet 3 AZIMUTH 47 MCg'OR 4 57\ 59 43 4/ /9 l8 2/ 58 5 g SCAN BRWKE a? 63 8/ 53 a4 MOTOR MOTOR 78 85 & 75 2 7/ 7a 86 89 72 74 79 m 9/ 99 /0/ /05 a0 REVERSING M SWITCH 39 REVERSING SWITCH 39 L F/G 4 POWER SUPPLY INVENTOR JOHN E. DAWK/NS ATTORNEY United States Patent MOTOR REVERSING CONTROL WITH COUNTER.

WEIGHT TO REDUCE REACTION TORQUES John E. Dawkins, Cedar Rapids, Iowa, assignor to Coliins Radio Company, Cedar Rapids, Iowa, av corporation of Iowa Filed Feb. 27, 1963, Ser. No. 261,366 9 Claims. (Cl. 318-286) This invention relates to a means for dynamically balancing a supporting structure.

Towers are often used to support antennas or other elements which are periodically moved. For example, some radio antennas must be oscillated back and forth to scan Another object of this invention is to provide a stable platform for an antenna or other device.

A feature of the invention is found in the provision for a supporting structure for an oscillating device such as an "antenna" which incorporates a counter-rotating counterweight to reduce the mechanical stresses in the supporting tower.

Further features, objects and advantages of thisinvention will become apparent from the following descriptionand claims when read in view of the drawings in which:

FIGURE 1 illustrates a supporting tower with a partial cutaway view of thescanning and counterweight structure;

FIGURE 2 is a sectional view of the scanning drive and counterweight shown in FIGURE 1;

FIGURE 3 is a sectional view of the counterweight structure, and; FIGURE 4 is an electrical schematic illustrating the control system for the apparatus.

' FIGURE 1 illustrates a supporting mast 10 which is imbedded at one end thereof in a ground support 11. An antenna 12 or other structure is supported adjacent the top end of the mast 10 for a rotational motion relative to the mast. The antenna 12 is counter-balanced by a counterbalance weight 13 to balance it. A cylindrical cover member 14 is attachedto the antenna 12 and has a gear 16 attached to its lower surface. The gear 16 meshes with a gear 17 carried on a shaft 19 of a scanning motor 18. Shaft 19 also extends through a braking motor 21. The motors 21 and 18 and related structures are rotatably supported from the mast 10 by a bracket 22 and bearing 23.

An azimuth drive motor 24 is supported by bracket 22 and has a vertical output shaft 26 which carries a gear 27. Gear 27 meshes with a gear 28 which is nonrotatably attached to shaft 10.

A counterweight structure designated generally as 29 is rotatably supported by bearing 31 relative to mast It A gear 32 is attached to the upper surface of counterweight 29 and meshes with gear 17 that is driven by the scanning motor 18 and the braking motor 21.

As best shown in FIGURES 1 and 3, a pair of snubbers 33 and 34 are mounted between the member 14 and the counterweight 29 so as to limit the relative motion of. the counterweight and the antenna structure. For example, a pair of snubbers 33 and 34 extend upwardly from the counterweight 29 and a second pair of snubbers 36 and 25 extend downwardly from the member 14. Flexible bumper pads 37 are attached to opposite ends of the bumpers 33 and 34 to cushion the impact when the snubbers engage. A reversing switch 38 is attached to the 'snubber 36 so that it engages snubber 34 and is switched thereby when the snubbers engage. A reversing switch 39 is mounted on the snubber 25 and engages the snubber 34 on contact.

FIGURE 4 illustrates the electronic schematic for operating the unit. The azimuth motor 24 has a pair of leads 4%? and 41 which are connected to a pair of electrical brushes 42 and 43 that are supported by a bracket 44 from bracket 22. The brushes 42 and 43 engage slip rings 46 and 47 which are insulatingly mounted on the mast 19. A pair of supply lines 48 and 49 are connected to the slip rings 47 and 46 respectively, and passed down the mast and an azimuth motor switch 51. The azimuth motor switch 51 is a double-pole switch that may be thrown to a first position to engage contacts 52 and 53, and to a second position to engage contacts 54 and 55. Contacts 52 and 55 are connected to one side of a power supply 56, and contacts 53 and 54 are connected to the other side of the power supply. Thus, the switch 51 may be moved to reverse the polarity of the power supplied to the azimuth motor through the slip rings. This allowsthe motor to be operated in opposite directions. The switch 51 also has an off position where contact is not made with the power supply, and the motor is stopped.

The braking motor 21 is connected by a pair of leads 57 and 58 to a pair or" brushes 59 and 6% which are supported by a bracket 61 from the bracket 22. The brushes 59 and 6t engage slip rings 62 and 63 which are insulatingly mounted on the mast 10. Supply lines 64 and 65 extend from slip rings 62 and 63 respectively, to a brakernoto-r switch 66. Brake-motor switch 66 is a double-pole switch, and has a first pair of contacts 67 and 68 that are connected together, and to one side of the power supply 56. The switch 66 has a second pair of contacts 69 and 70 which are connected together, and to the other side of the power supply. The switch 66 may be placed in one of three positions: a center disconnect position; a second position wherein the switch contacts connect leads 64 and 65 respectively to the contacts 67 and 70; and a third position wherein the switch connects leads 64 and 65 to contacts 69 and 68.

The scan motor 18 has a pair of output leads 71 and 72 which are connected to brushes 73 and 74 mounted on bracket 61. The brushes 73 and 74 engage slip rings 75 and 76 insulatingly mounted on mast 10. Another pair of slip rings 77 and 78 are insulatingly supported on the mast, and slip ring 77- is electrically connected to slip ring '75 by the lead 79. Slip ring 76 is electrically connected to slip ring 78 by the lead 80.

Brushes 81 and 82 are supported by the bracket 44 and engage slip rings 77 and 78 respectively. Brush 81 is electrically connected by lead 83 to a movable contact 84 of reversing switch 38. Lead 85 is connected to brush 82 and to movable contact 86 of reversing switch 39. The movable contacts 84 and '86 are mechanically connected together. Movable contact 84 engages either stationary contact 87 or stationary contact 88. Movable contact 86 engages either stationary contact 89 or stationary contact 90. A second reversing switch 38 has-four stationary contacts: 91, 92, 93, and94. Leads 95, 9.6, 97, and 98 connect corresponding stationary contacts 91 through 94 of reversing switch 38 with the stationary contacts 87 through 96 of reversing switch 39.

Reversing switch 38 has movable contacts 99 and 100 which are mechanically connected together. Movable contact 99 is connected by lead 101 to a brush 103, and

movable contact 101) is connected by lead 102 to a brush 104. Brushes W3 and 104 are supported by bracket 61, and engage respectively slip rings 165 and 106 which are 'insulatingly supportedby the mast 1d. Slip ring 103 is connectedby lead 107 to a motor scan switch 109. Slip ring 1% is electrically connected by leadlttfi to the motor scan switch 109. Switch 169 has a pair of stationary contacts 110 and 111 which are connected to the power supply 56.

In operation, the azimuth motor 24 may be energized by closing switch 51 to rotate the antenna and counterweight to a selected azimuth position. For example, if the an- .tenna is connected to a search radar, the motor 24 might be energized to rotate the counterweight and antenna to a particular azimuth. The azimuth motor-.24 is de-energized by opening switch 51. The motor stops and locks the shaft of the motor and gear 27 relative to the gear 28. The sector scanning motor 18 is then energized by closing switch 109. Motor 18 drives the antenna through the gears 17 and 16 while simultaneously driving the counterweight 29 in the opposite direction due to themeshing of gear 17 with gear 32. When the snubbers 2S and 36 engage the snubbers 33 and 34, reversing switch 38 or 39 is thrown to its other position resulting in a reversal of the direction of the motor 18. This causes the counterweight and antenna to reverse directions of rotation until the snubbers are'engaged in the other direction. When this occurs, the other switch 38 or 3-9 will be moved to its other position to once again reverse the motor 17. Sector scanning will continue as long as the motor 18 is energized. If, during this scanning, it is desired to stop the antenna at a particular azimuth, the motor 13 is deenergized, and the motor 21 is energized by closing switch 66 to stop the antenna and counterweight through gears 17, 16 and 32 at a desired location. The braking motor 21 is energized only long enough to stop the antenna at a particular azimuth.

The mast is shown as a hollow tube; however, the

principles of this invention are applicable to any tower configuration. a

The counterweight reduces the vibrations in the tower during scanning because it rotates in a direction opposite to the antenna structure and would thus tend toset up torsional vibrations opposite to those set up by the an- ,to a preferred embodiment, changes and modifications may be made which are within the full intended scope'as defined by the appended claims.

I claim: I 1. A vibration eliminating device for a support means comprising a utilization device rotatably supported by the support means, a counterweight rotatably supported by the support means adjacent the utilization device, a motor means rotatably supported by the support means and con- .nected tothe utilization device and the counterweight to rotate them in opposite directions, so that the etiects of the utilization device on the support means are offset by the counterweight.

2. In apparatus according to claim 1, means for reversing the motor means for reversing direction of rotation of the counterweight and the utilization device.

3. A vibration reducing system for a supporting mast comprising a utilization device rotatably supported by the mast, a counterweight rotatably supported by themast adjacent the utilization device, and means for driving the utilization device and the counterweight in opposite di rections, a snubber attached to the utilization device, a second snubber connected to the counterweight, firstand second reversing switches mounted on the snubbers and connected to the means for rotating the utilization device 4 and counterweight, and one of said reversing switches energized each time the snubbers engage to reverse the direction of rotation of the utilization device and the counterweight.

4. In apparatus according to claim 3, bumper pads attached to both ends of one of said snubbers so that when the snubbers engage the utilization device and counterweight will be eased to a stop.

5. A vibration reducing system for asupporting mast comprising a utilization device rotatably supported by themast, a counterweight rotatably supported by the mast adjacent .the utilization device, a motor means geared to the utilization device and to the counterweight to simultaneously drive them in opposite directions, and a pair of reversing switches electrically connected to the motor means so that the motor means is reversed in direction of rotation upon engagement of the snubbers to cause the utilization device and counterweight to oscillate back and forth relative to the support mast.

6. A vibration eliminating device for a support meansv comprising a utilization device rotatably supported by the support means, a counterweight rotatably supported by the support means adjacent the utilization device, a motor means rotatably supported by the support means and connected to the utilization device and the counterwewight to rotate them in opposite'directions, an azimuthmotor rotatably supported by .the support means withthe first motor means, a gear nenrotatably supported to the support means, and the azimuth motor geared'to the gear to rotate the first motor means and its related structure,

a mounted on the same drive shaft as the first motor to stop said utilization means and counterweight at anydesired position. a y

9. In apparatus according to claim 7, electrical circuitry connected to the first motor means and the reversing switches, and a power supply connected to the electrical OTHER REFERENCES Publication: Opposed Flywheels for Smoother Feed,

Product Engineering, volume 29, No. 33, page 66, Aug. 18, 1958.

oars L. RADER, Primary Examiner. 

1. A VIBRATION ELIMINATING DEVICE FOR A SUPPORT MEANS COMPRISING A UTILIZATION DEVICE ROTATABLY SUPPORTED BY THE SUPPORT MEANS, A COUNTERWEIGHT ROTATABLY SUPPORTED BY THE SUPPORT MEANS ADJACENT THE UTILIZATION DEVICE, A MOTOR MEANS ROTATABLY SUPPORTED BY THE SUPPORT MEANS AND CONNECTED TO THE UTILIZATION DEVICE AND THE COUNTERWEIGHT TO ROTATE THEM IN OPPOSITE DIRECTIONS, SO THAT THE EFFECTS OF THE 